Technical Field
The embodiments herein generally relate to the field of pressure/flow control of gases and fluids, more specifically, it relates to a multi nozzle device assembly, which enables precise control and regulation of gas and fluid pressure and/or flow.
Related Art
Pressure/flow of fluid/gas is often used to operate/move mechanical parts in a machine or mechanical systems. Generally, pressure/flow of liquid/gas is used to achieve a work done in a mechanical system. Various control devices that are operative to vary the pressure of the fluid/gas and are operative to control pressure or flow (change the flow direction for example) based on a feedback or excitation signal are employed. The pneumatic flapper valve control mechanism is one such device/method generally used in these applications. The flapper valve are used in various applications such as but not limited to: pressure control valve, pressure to electrical transducer (servo valve), membrane control system, Instrument Pressure (I/P), Axial piston pump control, Pressure compensated flow control valves, steam boilers, tracer lines, ironers, storage tanks, acid baths, storage calorifiers, unit heaters, heater batteries, OEM equipment, distribution mains, boiler houses, slow opening/warm-up systems with a ramp and dwell controller, pressure control of large autoclaves, pressure reduction supplying large steam distribution systems, desuperheaters, controlling pressure to control temperature, blow-through drying rolls in a paper mill, dairy cream pasteurizer etc.
FIG. 1A shows the conventional nozzle flapper valve to illustrate the basic principle of the nozzle flapper valve. The entity 100 depicts the conventional nozzle flapper valve to illustrate the basic principle of the nozzle flapper valve along with the drawbacks and limitation involved in the conventional flapper valve. Further the conventional nozzle flapper valve 100 comprises of flapper with a plate shape body with surface arranged to be at right angles with the axis of the nozzle 115.
In the flapper valve control, it is experienced that the effective range of the opening that controls the pressure is limited to less than a millimeter (Δx). Such limitation implies that the mechanical arrangement operating to move the flapper needs to be very precise and has within 1 mm as its dynamic adjustable range. Beyond this distance, the controlling effect cease. In some cases, the backlash of other connected mechanical parts may be of such magnitude, which could itself be more than the working range of the conventional flapper valve. Further, due to the angular orientation of the flapper and the orifice (nozzle of the flapper valve), there is bound to be air leakage leading to inaccurate sealing and poor pressure control.
FIG. 1B is an example of the conventional nozzle flapper valve operative in an example mechanical system. As shown, the nozzle flapper control device 101 comprises an exciter 190 as a primary vibrating source, which sets up or generates the vibrations with a corresponding amplitude and frequency on its output surface 195. The magnitude/amplitude and frequency of the exciter 190 imparting vibration on its output surface 195 may vary in time. A main cylinder 120 may be placed on the vibrating surface. As shown in the FIG. 1B, the transmission of the vibration from surface 195 to surface 135 is damped by the orifice 130 on surface 125. At the top of the cylinder 120 a flexible diaphragm 135 covers the main cylinder 120, on the center of which a payload 140 of mass M is placed. This payload 140 receives this transmitted vibration. A bell crank lever 180 senses the position of the payload 140. The bell crank lever 180 senses the vibration with the help of mechanical coupling 145 and translates the vibration to a flapper 150. The flapper 150 covers or uncovers a nozzle 155 depending on the position of payload 140.
Hence, covering the nozzle 155 connected to the cylinder 120 as shown. This nozzle 155 allows the leakage of the compressed air. The gap between the nozzle 155 and the flapper 150 is controlled by the movement of the flapper 150, thereby controlling the pressure in a way it counteracts the originally induced vibration in mutually opposite direction. Such controlling operation happens until an equilibrium status is reached and hence nullifies the originally induced vibration by the primary vibrating source exciter 190 by managing the pressure depending upon the distance of the flapper 150 from the nozzle 155. The compressed air (pneumatic) chamber 160 is the medium for the transfer of vibration from source exciter 190 to the payload 140. Such conventional nozzle flapper control device (described in FIG. 1) will have effective feedback limit of less than 1 mm working range of the flapper valve.
FIG. 1C is a table showing the working range of the conventional flapper valve.
FIG. 4 is another example of application of flapper valve. Shown there is a differential pneumatic vibration control arrangement for pneumatic control system. As shown here, it may have an electrically driven system to sense the source vibration like sensor mechanism driver 460 with a pair of coils or solenoids 420 and Ferro-magnetic plate 405. This may result movement of flapper control arm 410. In differential pneumatic vibration control arrangement shown here may have a pair of vibration feedback for left and right pneumatic systems. The right control system may have right nozzle 425, pneumatic input 435 and pneumatic output 450. The left control system may have left nozzle 430, pneumatic input 445 and pneumatic output 455. The vibration sensor 465 may be connected to the mechanical vibration to electrical signal converter with its final stage as sensor mechanism driver 460. This mechanical vibration to electrical signal converter and sensor mechanism driver 460 may drive individual solenoids to control the left 475 and right 470 flaps.
FIG. 7A is another example of differential pneumatic control arrangement using four way flapper nozzle. Here the actuator piston moves sideways in left or right motion in a chamber 745 with the help of the flow of the pressurized fluid passing through openings 735 and 740. 725 and 730 are constant orifices at both ends. 715 and 720 are two nozzles controlling the pressure on either side of the piston ring inside the chamber 745. The Flapper 710 controls the orifice areas of both the nozzles. Thus, the piston movement from left to right or vice versa is achieved by controlling the movement of the flapper 710. As mentioned, since the flapper's working range is limited, the fine control of the movement of the piston is not possible in this arrangement. Further, due to leakage between the flapper and nozzle, significant amount of energy is wasted.
Accordingly, a flow/pressure control valve is desirable that overcome above limitation while providing the operation of the flapper valve.